One by one add all the vegetables in the oil and fry it. Keep in mind u should add brinjal or eggplant at the last. Once all the veggies r cooked it's time to add the masalas. Add roasted spice, salt and sugar to taste. On the other hand make a fine paste of black, yellow mustard seeds and green chillies. Add the paste. Put the fried bitter gourd also. Cook it very well for around 15 mins on medium flame.